New 'sticky' chip increases detection of metastatic cancer cells

The ability to test the efficacy of chemotherapy in cancer patients has been hampered by the fact that cancer cells can float free in the bloodstream and carry the disease to other parts of the body--a process known as "metastasis." But a new "sticky" silicon chip may hold the key to detecting and collecting these cancer cells from a patient's blood, according to a recent article in the journal PLoS One.

A research team at Weill Cornell Medical College in New York City and Cornell's College of Engineering in Ithaca, N.Y., has built this chip into a device that captures a relatively high concentration of circulating tumor cells (CTCs) from patients with prostate cancer. In the device, known as Geometrically Enhanced Differential Immunocapture (GEDI), is an array of posts coated with antibodies that stick to cancer cells. Each just a few millionths of a meter in diameter, the posts are arranged so that they capture only cancer cells, which are slightly larger than normal cells that flow past in the blood stream.

After the test the chip is removed from the device, and the researchers extract captured cells for analysis. In one experiment with a blood sample containing 200 milliliters of CTCs and 5 billion blood cells, the device captured 170mL of CTCs and only 91mL of irrelevant blood cells. Compared with a similar search for CTCs using a commercially available device, GEDI was able to detect between two and 400 times as many CTCs per milliliter.

The ability to measure the amount of CTCs in a patient's bloodstream may have applications that go beyond prostate cancer, according to the paper. It may also help researchers better understand the biology of metastasis and develop new treatments.

The chip, known as, or GEDI, is scheduled to go into the clinical trial phase later this year, according to an announcement from Cornell.

Other breakthroughs are being reported in cancer detection, as well. According to a recent article in the Journal of the American Medical Association, for example, adding ultrasound and MRI imaging to the screening protocol for breast cancer could significantly increase the ability to find breast cancer. Of course, that could result in overdiagnosis--not to mention a huge increase in cost.

To learn more:
- read the PloS One study
- here's the Cornell announcement